Gun feeding mechanism



y 21, 1957 c. E. SIMPSON GUN FEEDING MECHANISM 2 Sheets-Sheet 1 FiledOct. 29, 1952 INVENTOR. Clarence E 5im :|sur1. BY v v v flrr'ozlvsrs' y21, 1957 c. E. SIMPSON GUN FEEDING MECHANISM 2 Sheets-Sheet 2 Filed Oct.29, 1952 INVENTOR. I: lure-nae E-51HLPE|DI1 n'rrozrvsns 2,792,761Patented May 21, 1957 GUN FEEDKNG MEHANISM Clarence E. Simpson,Wilbraham, Mass assignor to the United States of America as representedby the Secretar-y of the; Army Application October 29, 1952, Serial No.317,605

6 Ciairns. (Cl. Si -33) (Granted under Title 35', U. S. Code (1952),sec. 266) The invention described herein may be manufactured and used byor for the Government for governmental purposes without the payment ofany royalty thereon.

This invention relates to cartridge feeding mechanisms for automaticfirearms and is more particularly directed to improved means fortransferring cartridges from a transversely fed linked belt to thefiring chamber in the barrel.

One of the major problems resulting from the rapid rate of fire ofautomatic firearms is the obtaining of reliable feeding of thecartridges to the firing chamber from a continuous source of supply,such as a belt or magazine, so that jamming and misfire will not occur.

One means of feeding cartridges to an automatic firearm utilizes adisintegrating cartridge belt and a feedwheel to move the belt andcartridges therein to the feedway of the firearm. In such firearms,however, it is difiicult to deliver the cartridges to the feedway indirect alignment with the axis of the firing chamber inasmuch as thecartridge links of the belt and the sprocket portions of the feedwheelengaging the indexed cartridge would interfere with the weapons bolt inits reciprocal travel which must be in alignment with the axis of thefiring chamber. Hence, the cartridges have to be removed from the beltand then moved angularly therefrom to the firing chamber whichnecessitates their undergoing a number of changes of direction andspeed. For example, a cartridge is moved into the feedway by thefeedwheel, stopped in index position, angularly inclined toward thefiring chamber, picked up by the breech bolt traveling at a fast rate ofspeed, disengaged from the belt, moved angularly toward the chamber andafter axial alignment therewith, thrust home.

Because of the rapid rate of fire of automatic firearms, these changesof direction and speed take place within a fraction of a second.Obviously, therefore, it is important that they be accomplished assmoothly and precisely as possible to prevent the cartridges getting outof control and jamming in the feed channel leading to the firingchamber. One of the critical moments in the feeding cycle occurs whenthe cartridge is being directed angularly from the belt to the firingchamber. The conventional means of deflecting the cartridge from thebelt to the firing chamber comprises a rigid guide plate, adjacent thefeedway, which engages the nose of the cartridge as it is being centeredby the feedwheel. This engagement starts the depression of the cartridgewhich is further depressed while being thrust forwardly by the breechbolt. This arrangement, however, has the disadvantage that when the noseof the cartridge strikes the guide plate the impact is so great that thecartridge frequently gets out of control and becomes jammed in thefeedway. Then, too, any oscillation of the belt during entry into thefeedway affects the force with which the cartridges strike the guideplate and so varies their course to the firing chamber.

Accordingly, it is an object of this invention to prowheel anddisintegrating cartridge belt, an improved feeding mechanism which issimple and rugged in construction and reliable in operation.

It is a specific object of this invention to provide a feeding mechanismfor automatic firearms wherein the angular depression of the cartridgeis effected by a movable depressor member which acts on counter-recoilafter the cartridge has been fully indexed in the feedway during recoilthereby assuring that the cartridge is positively aligned with thefiring chamber and that each cartridge is depressed with the same degreeof force.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

Fig. l is a fragmentary longitudinal sectional view of the feedingmechanism of this invention incorporated in a firearm and shows thedepressor member directing the cartridge into the firing chamber;

Fig. 2 is a section on line 22 of Fig. 1

Fig. 3 is a bottom view of the cam slot in the driving member of thefeeding mechanism;

Fig. 4 is a fragmentary sectional bottom view of the feedwheel showingparts of the clutch mechanism therein;

Fig. 5 is a fragmentary top View of the receiver with the cover removed;and

Fig. 6 is a perspective view of the cartridge depressor member.

Referring to the drawings, there is shown in Fig. 1 a firearm having atubular-like receiver 12 with a hollow cylindrical sleeve 13 securedwithin the forward end thereof, and a barrel 14 removably mounted to thesleeve. Barrel 14 is provided with a conventional cartridge cham-. ber15. A rectangular channel 9 is provided in sleeve 13 adjoining chamber15 so as to be in axial alignment therewith, and is arranged to receivethe forward end of a longitudinally reciprocating bolt 34.

In the upper portion of receiver 12, adjacent sleeve 13, there isprovided a rectangular slideway 16 formed by side and end walls 17 and18 respectively, which project integrally upward from receiver 12.Longitudinal grooves 19 extend along the interior surfaces of each wall17 and are arranged to slidably engage mating longitudinal shoulders 20along the sides of an actuating slide 21 provided on the rear end of agas actuated operating rod. Fixedly mounted by any suitable means to theupper surface of slide 21 is a rectangular lug 22 disposed angularly tothe longitudinal axis of slide 21 in a manner to be described later.

Rearwardly of slideway 16 there is provided in receiver 12 a feedwayportion 8 wherein the front wall thereof is formed by wall 18 ofslideway 16. Feedway 8 is also provided with a rear wall 24 and alongitudinal side Wall 25 which extends integrally upward from the rightside of receiver 12. The top surface of Walls 24 and 25 of feedway 8 andwalls 17 and 18 of slideway 16 lie in the same plane to form a seat fora cover 33. On the left side of feedway 8 is an arcuate ramp portion 26which is slightly longer than a cartridge 27 and provides a passagewayfor entry of a cartridge belt. Said cartridge belt comprises a series ofcartridge links, such as is shown by 29, connectedly hinged bycartridges 27; Directly opposite ramp 26, is an exit 28 in wall 25 offeedway 8 through which the empty cartridge links 29 are ejected aftercartridges 27 have been stripped therefrom. The bottom of feedway 8 isconcave as shown at 30 and connects ramp 26 with exit 28. In the centralportion of fecdway 8 there is provided a longitudinal slot 31 whichcommunicates with the interior of receiver 12, slot 31 having forwardlyand outwardly, oppositely tapering sides Wide enough at the forwardmostend to permit one of cartridges 27 to pass therethrough.

Provided in the under side of receiver 12 below slot 31, is an ejectionport 32 for the fired cartridge cases. On either side of port 32 withinreceiver 12, are a pair of longitudinal ribs 33 which slidably supportbolt 34 and are therefore in axial alignment with the lower corners ofrectangular channel 9. Bolt 34 is a substantially rectangular memberhaving a spring-biased extractor 35 mounted in the bottom of the frontend thereof and a resilient ejector 36 at the top thereof. A cartridgerammer 37 is integrally combined with ejector 36 and is normally biasedupwardly intoslot 31.

Cover 38 is pivotally hinged to receiver 12 forward of slideway 16,'asshown at 81 in Fig. 1, and the underside thereof is arranged to matewith walls 17 and 18 of slideway 16, and walls 24 and 25 of feedway 8.Cover 38 is secured in closed position by a latch as shown at 39.Longitudinally mounted in cover 38 by means of suitable holes in eitherend wall thereof is a rod 42. The rear end of rod 42 is drilled out toreceive a plunger 41 which is actuated by a suitable coil spring (notshown) to resiliently bias latch 39 downwardly. Rotatably mounted on rod42 are a driving member 43, a co-acting clutch 44 and a sprocketfeedwheel 45, one end of which 1is engageable with clutch 44 in a mannerto be described ater.

Driving member 43 comprises a forwardly extending stern portion 46 andan enlarged head portion 47 at the rear end thereof. On stern portion 46are a pair of protruding lips 48 which form therebetween a helical slot49, best shown in Fig. 3, which receives lug 22 of actuating slide 21when cover 38 is in closed position. The angle of lug 22 conforms to thehelix angle of slot 49 so that it readily slides therein. The helixangle and length of slot 49 is such that when lug 22 is moved byactuating slide 21 of the operating rod from the foremost to therearmost end of slot 49, driving member 43 is rotated of a turn in acounterclockwise direction, as shown in Fig. 2. Provided in stem 46,adjacent head 47, is an elongated recess 52 which is longitudinallyaligned with the forward end of slot 49.

Mounted on drivingmember 43 is a cartridge depressor member 54 having acollar portion 53 which surrounds head 47 contiguous the rear surface ofan annular flange 51 provided thereon. A depressor portion 55 is fixedlysecured to collar 53 and extends forwardly therefrom. Said depressor 55terminates at the forward end thereof in a finger portion 60 whichprojects upwardly into recess 52 and thereby secures cartridge depressormember 54 against rotation relative to driving member 43 and in linewith the forward end of slot 49. The underside of depressor 55 slopesforwardly and downwardly and comprises a pair of longitudinallyadjacent, planar surfaces 58 and 59 inclined, relative one to the other,at an obtuse angle. The planar surface adjacent wall 25, hereinafterreferred to as directing surface 58, acts to direct the cartridges 27from feedway 8 to chamber 15 as they are being propelled forwardly bybolt 34. When lug 22 of actuating slide 21 is in its normal forwardposition in slot 49, driving member 43 is positioned so that depressorportion 55 is centered in feedway 8 over slot 31 and directing surface58 is perpendicular to the plane formed by the longitudinal axes of rod42 and barrel 14. The second planar surface 59, hereinafter referred toas camming surface 59, acts as a means for camming cartridges 27 intoposition to be engaged by directing surface 58 during the rotationimparted to driving member 43 during the counter-recoil of slide 21.

Rcarwardly adjacent head 47 of driving member 43 is feedwheel 45 bywhich the cartridge belt is drawn into feedway 8. In the forward portionof feedwheel 45 there is provided an axial cylindrical cavity 64arranged to re ceive a reduced diametral portion 57 of clutch 44 and acoil spring 63. Said coil spring 63 biases clutch 44 resiliently againstdriving member 43 so that a plurality of equally spaced ratchet teeth 61on the rearward face of driving member. 43 engage mating ratchet teeth62 on the forward face of clutch 44. Oppositely disposed, radiallyprojecting keys 65 on the forward end of clutch 44, are slidablyreceived by elongated keyways 66 in the forward end of feedwheel 45 soas to secure the clutch to the feedwheel and also allow it to be forcedrearwardly in the feedwheel by driving member 43, as will be explainedlater.

Adjacent each end of feedwheel 45 are sprocket wheels 67 having aplurality of radial arms 68 spaced by arcuate recesses 69 shaped to fitaround the case of cartridge 27. The ends of arms 68 terminate at theradial center of the case of cartridges 27 so as to equalize theircontact on the circumference, of the cartridge case as it is being drawnthereby into feedway 8. This aids in reducing any unbalanced contact oncartridge 27 which might cause it to buckle and jam while being fed.Sprocket wheels 67 and ratchet teeth 61 and 62 on driving member 43 andclutch 44, respectively, are so arranged that when driving member 43 isin the position occupied when actuating slide 21 is in battery position,and, when ratchet teeth 61 and 62 are in full engagement, thelongitudinal axis of the arcuate recess 69 indexed in feedway 8 is inline with the longitudinal axis of depressor portion 55 of cartridgedepressor member 54.

Encircling feedwheel 45 between sprocket wheels 67 are a plurality ofratchet teeth 70 and annular bearing surfaces 71 on either side thereof.Extending transversely of feedwheel 45 and adjacent ratchet teeth 70, isa leaf spring 72 having a planar portion 73, which abuts upwardlyagainst shoulders 74 provided in either side of cover 38. Projectingdownwardly from one end of portion 73 is an arcuate portion 75, whichencircles that portion of the ratchet teeth which lie adjacent exit 28in receiver 12. Projecting from the opposite end of portion 73 is an armmember 76 that projects downwardly to engage ratchet teeth 70 and actsas a resilient stop for preventing counter-rotation of feedwheel 45.

A longitudinal slot 77 is provided in planar portion 73 to receiveratchet teeth 70, permitting planar portion 73 to press resil-ientlyagainst bearing surfaces 71 of feedwheel 45 and thereby hold planarportion 73 firmly against shoulders 74 and secure spring 72 to cover 38.

As has been explained, when cover 38 is closed and secured to receiver.12 by latch 39, rectangular lug 22 on actuating slide 21 is received byhelical slot 49 in driving member 43. During the reciprocal travel ofactuating slide 21, lug 22 moves from one end of helical slot 49 to theother producing an oscillating rotation of driving member 43. Whenactuating slide 21 is moved rearwardly during recoil, the rotation givendriving member 43 is transmitted to clutch 44by engagement of the matingratchet teeth 61 and 62 on the. driving member and clutch, respectively.This rotation is in turn transmitted to feedwheel 45 by keys 65 onclutch 44 which engage keyways 66 on feedwheel 45.

The return of actuating slide 21 to its normal forward position bysuitable spring means 5(not shown), rotates driving member 43 in theopposite direction. Feedwheel 45 will remain stationary, however, as itis held against counter-rotation by arm 76 of leaf spring 72 engagingthe suitably positioned ratchet teeth 70 on the feedwheel. Thecounter-rotation of driving member 43 is possible, while feedwheel 45 islocked, because the angular sides of ratchet teeth 61 and .62 cam clutch44 resiliently into feedwheel 45 with keys 65 reciprocably sliding inkeyways 66 thus allowing driving member 43 to move independently. At theend of the return stroke of actuating slide 21,.ratchet teeth 62 passover the :apexes of ratchet teeth 61 allowing clutch 44 to moveresiliently 55 at the same time is vertically centered above slot 31positioning cartridge 27 vangularly' downward in the direction ofchannel 9 in sleeve 13.

To fire the weapon, the trigger mechanism (not shown) is actuated torelease bolt 34. When bolt 34 is released, it moves forwardly on ribs 33under propulsion of suitable spring means (not shown). As bolt 34 passesunder slot 31, rammer 37 projects progressively upward therethrough tocontact the base of cartridge 27 and push it through cartridge link 29which is open at the bottom to permit unobstructed passage of rammer 37therethrough. Cartridge link 29 is held in feedwheel 45 while cartridge27 is being stripped therefrom by mechanism more fully described andexplained in U. S. Patent No. 2,648,258. While cartridge 27 is beingpushed forwardly by rammer 37 it moves forwardly in contact withdirecting surface 58 of cartridge depressor 55 and down through slot 31.The tapering sides of slot 31 and arms 68 of feedwheel 45 assist inkeeping cartridge 27 directed toward channel 9 of sleeve 13. Ascartridge 27 is moved forwardly, it progressively enters channel 9 ofsleeve 13 until aligned therewith and its base is in full contact withthe forward face of bolt 34 which forces the cartridge into firingchamber 15 and fires it by conventional means.

The gases created by the firing of cartridge 27 are bled from barrel 14into a cylinder (not shown) to force the operating rod and the attachedactuating slide 21 rearwardly. As has been previously explained, therearward travel of actuating slide 21 rotates driving member 43 to movecartridge depressor 54 out of the way of the incoming cartridge 27 asfeedwheel 45 is also being rotated to index such cartridge in feedway 8.As cartridge 27 is being drawn into feedway '8 by feedwheel 45,cartridge link 29, freed during the previous cycle of fire, is ejectedthereby out of exit 28. Arcuate portion 75 of leaf spring 72 assures asmooth ejection of cartridge link 29 and thereby prevents thepossibility of jamming between feedwheel 45 and cover '38. The rearwardstroke of actuating slide 21 also unlocks bolt 34 and propels itrearwardly with extractor 35 withdrawing the fired cartridge case. Whenactuating slide 21 reaches the limit of its rearward travel, it isimmediately returned to its normal forward position by suitable springmeans while bolt 34 continues rearwardly in receiver 12 to eject theempty cartridge case out of ejection port 32 and be either engaged bysuitable trigger mechanism or allowed to return and fire another round.In the meantime, the return stroke of actuating slide 21 counter-rotatesdriving member 43 to return cartridge depressor 54 to its normalposition. During this counter-rotation of cartridge depressor 54, camsurface 59 thereof depresses cartridge 27 which is held by feedwheel 45until surface 58 moves onto cartridge 27 which is thereupon ready to bepicked up by bolt 34.

it can readily be seen that inasmuch as the cartridge is depressed afterbeing aligned with the axis of the firing chamber and while it is firmlysecured in the feedwheel, and at rest, the likelihood of the cartridgejamming during feeding has been considerably reduced. It is also obviousthat there is here provided a feeding mechanism which is compact,simple, and rugged in construction.

I claim:

1. In a firearm having a longitudinally reciprocal bolt, a barrel, and afiring chamber in the barrel, the combination of a transverse feedwaylocated in a higher plane than the bolt and barrel, said feedway havinga longitudinal cartridge slot centrally thereof, a feedwheel rotatablymounted above said slot, means for intermittently rotating saidfeedwheel to advance a linked belt of cartridges along said feedway forpositioning the leading cartridge in parallel alignment with said slot,a rotatable cartridge depressor having a depending portion projectinginto said feedway and normally positioned in parallel alignment withsaid slot, means associated with said feedwheel for rotating said catridge depress-or to move said depending portion out of the path of theleading cartridge during the feeding movement thereof and for returningsaid depressor to the nonrotated position thereof subsequent to thefeeding movement of the leading cartridge but prior to the forwardmovement imparted thereto by the bolt, first cam means along the side ofsaid depending portion for inclining the leading cartridge downwardlytoward alignment with the firing chamber during the return of saiddepressor to the non-rotated position thereof, and second cam means onthe underside of said depending portion for progressively guiding theleading cartridge into the firing chamber during the delinking andchambering movements thereof.

2. In a firearm having a receiver, a bolt slidably mounted in thereceiver for longitudinal reciprocal movement, a barrel, and a firingchamber in the barrel, the combin'a tion of a cover hingedly secured atthe forward end thereof to the receiver, the underside of said cover andthe top of the receiver cooperating to define a transverse feedway in ahigher plane than the bolt and barrel, said feedway having alongitudinal cartridge sl-ot centrally thereof, a feedwheel rotatablymounted in said cover above said slot, means for intermittently rotatingsaid feedwheel to advance a linked belt of cartridges along said feedwayfor positioning the leading cartridge in parallel alignment with saidslot, a cartridge depressor rotatably mounted forwardly of saidfeedwheel and having a depending portion inclined forwardly anddownwardly to normally proje'ct vertically into said feedway in parallelalignment with said slot, means associated with said feedwheel forrotating said cartridge depressor to move said depending portion out ofthe path of the leading cartridge during the feeding movement thereof,means for preventing the rotation of said feedwheel during the return ofsaid depressor to the nonrotated position thereof and prior to theforward movement imparted to the leading cartridge by the bolt, firstcarn means along the side of said depending portion of said depressorfor inclining the leading cartridge downwardly toward alignment with thefiring chamberduring the return of said depressor to the non-rotatedposition thereof, and second cam means on the underside of saiddepending portion of said cartridge depressor for progressivelyincreasing the inclination imparted to the leading cartridge by saidfirst cam means, said second cam means being arranged to cooperate withsaid slot in said feedway for guiding the leading cartridge out of thelink engaged therewith and into the firing chamber of the barrel.

3. In a firearm having a longitudinally reciprocal bolt, a firingchamber in axial alignment with the bolt, and means for intermittentlyfeeding a belt of linked cartridges transversely into the firearm abovethe bolt and parallel to the longitudinal axis thereof, the combinationof a cartridge depressor rotatably mounted in the firearm above and tothe rear of the firing chamber to normally depend into the feeding pathof the leading cartridge, a first cam surface disposed along the side ofsaid cartridge depressor nearest the leading cartridge, means forrotating said cartridge depressor in one direction to swing said firstcam surface out of the path of the leading cartridge during the feedingmovement of the belt and for rotating said cartridge depressor in theopposite direction during the interval between the intermittent feedingmovements of the belt but prior to the chambering movement of theleading cartridge whereby said first cam surface tilts the front end ofthe leading cartridge downwardly into alignment with the rear end of thefiring chamber, and a second cam surface on the underside of saidcartridge depressor for guiding the tilted cartridge into the firingchamber during the chambering movement imparted thereto by the bolt.

4. In a firearm having a concave transverse feedway, a bolt slidablydisposed below the feedway for longitudinal reciprocal movement, and afiring chamber in axial alignment with the bolt, cartridge feed meanscomprising a feedwheel rotatably mounted above the feedway, a drivingmember rotatable in either direction, clutch means interposed betweensaid driving member and said feedwheel for limiting rotation of thelatter in the feeding direction only, a cartridge depressor fixedlysecured to said driving member to normally depend into the feeding pathof the leading cartridge, 21 forwardly and downwardly inclined first camsurface disposed along the side of said depressor nearest the leadingcartridge, means for rotating said driving member in either directionwhereby counterclockwise movement thereof actuates said feedwheel toadvance the cartridge belt along the feedway and simultaneously swingsaid depressor out of the feeding path of the leading cartridge andclockwise movement of said driving member returns said cartridgedepressor to the normal depending position thereof whereupon said firstcam surface contacts the leading cartridge to tilt the front end thereofdownwardly into alignment with the rear end of the chamber, and aforwardly and downwardly inclined second cam surface on the underside ofsaid cartridge depressor for guiding the tilted cartridge into thefiring chamber during the forward movement imparted thereto by the bolt.

5. In a firearm having a receiver, a bolt slidably mounted in thereceiver for longitudinal recoil and counterrecoil movement, and afiring chamber in axial alignment with the bolt, the combination of aconcave feedway formed transversely across the receiver above the bolt,said feedway having a centrally disposed, forwardly diverging1ongitudinal slot, a cover hingedly secured to the forward end of thereceiver, a longitudinal rod rotatably mounted in either end of saidcover, a feedwheel fixedly mounted on said rod, sprocket means on saidfeedwheel for engaging a belt of linked cartridges disposed on saidfeedway when said cover is closed, a driving member fixedly mounted onsaid rod forwardly of said feedwheel, means for rotating said drivingmember in either direction during recoil of the bolt, clutch meansinterposed between said driving member and said feedwheel for limitingrotation of thelatter to the direction in which said sprocket meansadvances the cartridge belt along said feedway, and

a cartridge depressor normally disposed above said slot in said feedwayand in the feeding path of the leading cartridge in the belt, saiddepressor having a forwardly and downwardly inclined surface on theunderside thereof and a cam surface extending longitudinally along theside thereof and inclined upwardly and outwardly at an obtuse anglerelative to said inclined underside surface, means for mounting'saiddepressor on said rotatable driving member to swing out of the path ofthe leading cartridge in the belt during the feeding rotation impartedto said feedwheel and to swing into contact with the leading cartridgeduring rotation of said driving member in the opposite direction, saidlongitudinal cam surface being disposedso as to cam the leadingcartridge therebeneath and to simultaneously tilt the front end thereofdownwardly into alignment with the rear end of the firing chamber, theinclination of the underside of said depressor being arranged tocooperate with the diverging slot in the feedway to guide the tiltedcartridge into the firing chamber during the forward movement impartedthereto by the counterrecoiling bolt.

6. The combination defined in claim 5 wherein said means for mountingsaid depressor on said driving member comprises a collar portionextending upwardly from the rear end of said depressor, and a lugprojecting upwardly from the front end of said depressor, said drivingmember having a longitudinal slot in the underside thereof for receivingsaid depressor lug, said slot being of greater length than saiddepressor lug to permit said collar portion to slide onto the rear endof said driving member.

References Cited in the file of this patent UNITED STATES PATENTS1,446,388 Ludorf Feb. 2-0, 1923 2,113,202 Stange Apr. 5, 1938 2,453,786Dixon Nov. 16, 1948 2,454,251 Hamilton Nov. 16, 194? FOREIGN PATENTS67,215 Denmark July 12, 1948

